Variable cam corrector mechanism



July 5, 1966 E. WEISS 3,258,982

VARIABLE CAM CORRECTOR MECHANISM Original Filed March 21, 1963 2Sheets-Sheet l g 1 34 as FIG. 1

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1 N VEN TOR.

ERNEST WE/SS HTI'ORIVEY July 5, 1966 E. WEISS Original Filed March 21,1963 2 Sheets-Sheet 2 I 5p m /A 42 INVENTOR.

ERNEST WE/SS United States Patent 3,258,982 VARIABLE CAM CORRECTORMECHANISM Ernest Weiss, Maywood, NJ., assignor to The BendixCorporation, a corporation of Delaware Continuation of application Ser.No. 266,891, Mar. 21, 1963. This application June 9, 1965, Ser. No.462,651 15 Claims. (Cl. 74393) The invention relates to a variable camcorrector mechanism and more particularly to an improved and simplifiedmechanism for adjusting the relation between rotary motions at input andoutput shafts by adding to or subtracting from the rotation imparted tothe output shaft by the input shaft in a highly accurate and precisemanner and to a mechanism which simplifies prior structures disclosedand claimed in US. Patent No. 2,896,464, granted July 28, 1959, to PaulL. Reuter and Ernest Weiss, and US. Patent No. 2,968,964, grantedJanuary 24, 1961 to Harry G. Anastasia and William F. Watson, nowReissue Patent No. 25,513 granted January 14, 1964, all of which patentshave been assigned to The Bendix Corporation, assignee of the presentinvention. The present application is a continuation of applicationSerial No. 266,891, filed March 21, 1963.

An object of the invention is to provide a simplified variable camcorrector mechanism including a flexible cam follower driven by an inputshaft and having a pin projecting from the cam follower in drivingrelation with a disc clamped to an output shaft in an arrangement inwhich flexing of the cam follower caused by the surface contour of acooperating cam will result in an angular motion being imparted to thepin projecting from the cam follower and resting against a polished facein the slot of the disc clamped to the output shaft so that a correctivemotion may be imparted to the output shaft to effect a desiredadjustment in the output shaft relative to the input shaft.

Another object of the invention is to provide in a mechanism of a typeincluding an input shaft, an output shaft, a device for drivinglyconnecting said input and output shafts, said connecting device beingrotatable by said input shaft, variable control gain means, and a camfollower means in contacting relation with said cam means and operatedthereby to adjust said connecting device so as to move the output shaftrelative to the input shaft, the improvement comprising: said connectingdevice including a pin carried by the cam follower, a slotted disccarried by the output shaft and the pin-mounted in driving relation inthe slot of the disc so as to drivingly connect said input and outputshafts and the pin being angularly adjustable by the cam follower meansfor actuating said disc so as to adjust the output shaft relative tosaid input shaft in accordance with the contour of the cam means.

Another object of the invention is to provide a device arranged toeffect correction of small angular errors found in electromechanicalcomponents.

Another object of the invention is to provide novel means to compensateor correct for those errors inherent in the accuracy limitations ofrotary electrical components; such as synchros, resolvers, or in thegear trains or driving connections therefor,

Another object of the invention is to provide novel rotating camcorrection means operable in conjunction with one of the limitedaccuracy electrical and mechanical components to effect a desiredcorrection.

Another object of the invention is to provide a compensating camcorrecting mechanism which may be directly assembled to the respectiveelectrical component and operable in conjunction with such component soas to reduce an angular inaccuracy arising from errors of :15 or 30minutes of arc to less than one minute of arc and to a device operableto correct inaccuracies attributable to 3,258,982 Patented July 5, 1966such angle-dependent errors such as electrical error output from suchelectrical component and/ or errors caused by imperfect gears, eccentricshafts, and accuracy limitations in rotary electrical components.

Another object of the invention is to incorporate in a variable camcorrector mechanism novel means to effect minute angular correctionwhile maintaining a reasonable sense of feel while adjusting to effectthe desired angle of correction.

These and other objects and features of the invention are pointed out inthe following description in terms of the embodiment thereof which isshown in the accompanying drawings. It is to be understood, however,that the drawings are for the purpose of illustration only and are not adefinition of the limits of the invention. Reference is to be had to theappended claims for this purpose.

In the drawings:

FIGURE 1 is a fragmentary assembly view illustrating a variable camcorrector mechanism embodying the invention and used in conjunction witha rotary electrical component to reduce angular inaccuracies arisingfrom errors in the electrical components and/ or errors caused byimperfect gears, or eccentricity in the output or input shafts, and likemechanical devices.

FIGURE 2 is an enlarged detailed sectional view of the hub assembly ofFIGURE 1 showing the operative relationship of the flexible cam followerdrive plate and the angularly adjustable drive pin projecting axiallyfrom the cam follower plate in driving relation with a slotted discclamped to the output shaft.

FIGURE 3 is an enlarged view of the slotted disc provided in thevariable cam corrector assembly of FIGURE 1 and clamped to the drivenoutput shaft.

FIGURE 4 is an enlarged detailed side view and FIG- URE 5 is an enlargeddetailed front view of the flexible cam follower drive plate embodied inthe variable cam corrector mechanism of FIGURE 1 and showing thelocation of the adjustable drive pin and the cam follower ball andretainer mounted on the plate.

FIGURE 6 is a detailed assembly view showing the variable cam correctormechanism of FIGURE 1 directly assembled on the driven shaft of a rotaryelectrical component, such as a synchro,

Referring to the drawing of FIGURE 1, there is indicated by the numeral10 a drive or input shaft operably connected by gears 12 and 13 to a camfollower assembly 14, including a hub 16 rotatably mounted on ballbearings 18 and 20 (FIGURE 2) carried by a sleeve 22 drivingly aflixedto a driven or output shaft 24. The sleeve has an annular flange 26 atone end to hold-the bearing 18 in place while the bearing 20 is held inplace on the sleeve 22 by a disc 30 clamped to the sleeve 22 by afastening screw 31. Further secured to the hub 16, at one end thereof isthe gear 13, while there is secured to the opposite end of the hub 16 aflexible cam follower drive spring 32, shown in greater detail inFIGURES 4 and 5. The flexible cam follower drive spring 32 includes ahub portion 31a for mounting the driver plate on hub 16 and a spring tabportion 33 secured to the hub portion at one end and separated therefromby a substantially U-shaped slot 35 extending around the hub portiontoward the end of the driver plate to permit the spring tab portion toflex relative to the hub portion. The base of the U-shaped slot isconcentric with the hub portion. A cam follower ball 34 carried in aretainer portion 36 is mounted on the spring tab portion 33.

Further, projecting from spring tab portion 33 of flexible cam followerdrive spring 32 is a drive pin 38 spaced angularly from cam followerball 34 substantially about the axis of rotation of cam follower drivespring 32. The drive pin 38 extends through and is freely movable in aslot 40 in the gear 13 while an end portion of 3 the drive pin 38 restsagainst the polished face of a slot .42 provided in the disc 30, asshown in FIGURES 2 and 3.

Further, the cam follower ball 34 carried in the retainer portion 36 isbest shown in FIGURE 1 and bears against the surface ofa flexible camplate 44 operatively supported by suitable adjustable mounting screws,two of which are shown in FIGURE 1 and indicated by the numerals 46 and48. The mounting screws 46 and 48 are arranged to vary the contoursurface of the flexible cam plate 44 and are adjustably mounted in asupporting plate 50.

An end portion 52 of the shaft 24 is rotatably mounted in ball bearings54 carried in the supporting plate 50 and the end portion 52 of theshaft 24 has aflixed thereto a suitable pointer 55 arranged to cooperatewith suitable indicia, not shown, on the supporting plate 50.

In the aforenoted arrangement, motion will be imparted by the driveshaft through the gears 12 and 13 to the hub 16 and cam follower driveplate 32 and thereby transmitted through the pin 38 to the disc clampedto the sleeve 22 and thereby drivingly connected to the driven or outputshaft 24 which in turn is drivingly connected through gears 60 and 61 toa rotary electrical component 64 which may be a conventional synchro,potentiometer, or any other electrical component.

In the iaforenoted arrangement inherent inaccuracies in the rotaryelectrical component 64 or in the gears, gear trains, or eccen-tricitiesof the operating shafts may be compensated or corrected through suitableadjustment of cam follower assembly 14. This is effected by the operatoradjusting the screws 46 and 48 carrying the flexible cam plate 44 so asto so adjust the contour thereof relative to the cam follower ball 34 asto cause an angular adjustment of the drive pin 38 to effect acompensating adjustment of the driven or output shaft 24 relative to theinput shaft 10 so as to thereby cause the output shaft 24 to lead or lagthe angular adjustment of the drive or input shaft 10 and therebycompensate for the :aforenoted inaccuracies.

The variable cam corrector mechanism, as shown in FIGURE 6, may bedirectly assembled to the driven shaft of the rotating electricalcomponent which may correspond to the shaft 24, shown in the hubassembly of FIGURE 2. In the arrangement of FIGURE 6, corre spondingnumerals indicate corresponding parts to those heretofore described withreference to the assembly view of FIGURES 1 and 2.

Operation of variable cam corrector mechanism In the assembly of thevariable cam corrector mechanism of FIGURES 1 and 6, rotation of thegear 13 by the drive shaft 10 and gear 12 will result in a simpletransfer of motion to the cam follower drive plate 32 to thereby causethe pin 38 to actuate the disc 30 and in turn drive the shaft 24operatively connected thereto through the sleeve 22 to rotate the shaft24 degree for degree in an identical manner as the gear 13 while the camfollower ball 34 will ride along the face of the flat cam 44.

However, upon set-ting the adjustment screws 46 and 48 in the supportingplate 50 so as to effect a distortion of the flexible cam plate 44, thecam follower drive plate 32 upon rotation of the gear 13 will beangularly positioned in following the contour of the cam plate 44 so asto in turn angularly position the drive pin 38 in the slot relative tothe gear 13, as best shown in FIGURE 6, and which angular adjustment ofthe drive pin 38 will in turn cause the plate 30 to be adjustedangularly relative to the gear 13 and thereby impart a compensatingangular adjustment to the driven shaft 24 to cause the angular positionof the driven shaft 24 to lead or lag the angular position of the driveshaft 10 so as to compensate for the inherent errors in the rotaryelectrical component 64, such as a synchro, or electrical resolver orpotentiometer, and also may serve to compensate or correct for thoseerrors in the assembly caused by imperfect gears or operating shafts ofthe gear trains.

It will be seen then that the variable cam corrector mechanism providesa novel arrangement of extreme simplicity in which a one piece flexiblecam follower and drive pin and cooperating slotted driven shaft discassembly permits elimination of the more complex conventionally usedball bearing hinges and shafts to eifect the desired correction orcompensation.

Although only one embodiment of the invention has been illustrated anddescribed, various changes in the form and relative arrangement of theparts, which will now appear to those skilled in .the art may be madewithout departing from the scope of the invention. Reference is,therefore, to be had to the appended claims for a definition of thelimits of the invention.

What is claimed is:

1. In a mechanism of a type including an input shaft, an output shaft, adevice rotatable by said input shaft for drivingly connecting said inputand output shafts, cam means, cam follower means coaxial with andengaging said cam means to adjust said connecting device so as to movethe output shaft relative to the input shaft, the improvementcomprising: said connecting device including a pin carried by the camfollower extending in a parallel and an offset position to said camaxis, a slotted disc carried by and in coaxial relation to the outputshaft and wherein the pin is slidably mounted in driving relation in theslot of the disc so as to drivingly connect said] input and outputshafts and the pin being angularly adjustable by the cam follower meansfor angularly actuating said disc so as to adjust the output shaftrelative to said input shaft in accordance with the contour of the cammeans to effect a desired lead or lag of the input shaft relative to theoutput shaft.

2. In a mechanism of a type including an input shaft, an output shaft, adevice rotatable by said input shaft for drivingly connecting said inputand output shafts, variable control cam means, cam follower meanscoaxial with and in contacting relation to said cam means and operatedthereby to adjust said connecting device so as to move the output shaftrelative to the input shaft, the improvement comprising: said connectingdevice including first coupling means carried by and radially offsetfrom the axis of said cam follow-er, second coupling means drivinglyconnected to and radially oifset from the output shaft and slidablyengaging said first coupling means, said first and second coupling meansbeing arranged in said coupling relation for drivingly connecting saidinput and output shafts in one sense, and said first coupling meansbeing operated by said cam follower means for angularly actuating saidsecond coupling means in a second sense so as to angularly adjust theoutput shaft relative to the input shaft in accordance with the positionof said cam means to effect a desired lead or lag of the input shaftrelative to the output shaft.

3. The combination defined by claim 2 in which the first coupling meansincludes a pin carried by the cam follower and projecting axiallytherefrom, and the second coupling means includes a disc drivinglyconnected to the output shaft, said disc having a slot in which said pinis slidably mounted in driving relation, the pin being effective todrivingly couple the input shaft to the output shaft in said one sense,and the pin being angularly adjustable by the cam follower so as toadjust the disc and thereby the output shaft relative to said inputshaft in accordance with the cont-our of the cam means.

4. A variable cam corrector mechanism comprising: an input shaft, anoutput shaft, a flexible cam track, means for supporting said flexiblecam track, said supporting means including a plurality of adjustablemembers for carrying the flexible cam track whereby adjustment of saidmembers may be effective to vary the contour of said cam track, a camfollower rotatably mounted on said output shaft and in a coaxialrelation to and in contacting relation with said cam means, meansdrivingly connecting said cam follower to said input shaft, a pinprojecting from said cam follower parallel to the axis of said camtrack, a disc drivingly connected to said output shaft, said disc havinga slot in which said pin is mounted in driving relation with said discto drivingly connect said input and output shafts in one sense, and saidpin being angularly adjustable by said cam follower for angularlyactuating said dis-c so as to angularly adjust the output shaft relativeto said input shaft in accordance with the contour of the cam track toeffect a desired lead or lag of the input shaft relative to the outputshaft.

5. Cam corrector mechanism for effecting a desired lead or lag of anoutput shaft driven by an input shaft, comprising a member fixed to theoutput shaft, cam means, cam follower means driven by the input shaftand including a flexible drive plate mounting a cam follower yieldinglyurged into engagement with the cam means and an element engaging themember so that rotation of the input shaft rotates the output shaft and,as the cam follower rides over the cam means, the element is advanced orretarded relative to the input shaft and provides for relative movementbetween the input and output shafts in accordance with the contour ofthe cam means to effect desired lead or lag of the output shaft relativeto the input shaft.

6. The structure of claim 5 wherein the driver plate comprises a hubportion for mounting the driver plate .and a spring tab portion securedto the hub portion at one end and separated therefrom by a slotextending around the hub portion toward the one end of the driver plateto permit the spring tab portion to flex relative to the hub portion,and .the cam follower and element being mounted on the spring tabportion.

7. The structure of claim 6 wherein said cam follower and element arespaced angularly substantially 90 degrees about their axis of rotation.

8. Cam corrector mechanism drivingly coupling an input shaft to anoutput shaft and effecting a desired lead or leg of the output shaftrelative to the input shaft, comprising a member fixed to the outputshaft, cam means, 0am follower means driven by the input shaft andincluding a flexible driver plate coaxial with the output shaft andmounting a cam follower yieldingly urged into engagement with the cammeans and an element engaging the member so that rotation of the inputshaft rotates the output shaft, and the cam follower and element beingspaced substantially 90 about their axis of rotation so that as the camfollower rid-es over the cam means, the element is advanced or retardedrelative to the input shaft and provides for relative movement betweenthe input and output shafts in accordance with the contour of the cammeans to effect desired lead or lag of the output shaft relative to theinput shaft.

9. Cam corrector mechanism for effecting a desired lead or lag of anoutput shaft driven by an input shaft, comprising a member fixed to theoutput shaft, adjustable cam means, cam follower means driven by theinput shaft and including a spring driver plate mounting a cam followeryieldingly urged into engagement with the cam means and an elementengaging the member so that rotation of the input shaft rotates theoutput shaft and, as the cam follower rides over the cam means, thespring plate flexes and the element is advanced or retarded relative tothe input shaft and provides for relative movement between the input andoutput shafts in accordance with the contour of the cam means to effectdesired lead or lag of the output shaft relative to the input shaft.

10. Variable cam corrector mechanism for effecting a desired lead or lagof an output shaft with respect to an input shaft, comprising a memberfixed to the output shaft and having an aperture therein, adjustable cammeans, cam follower means driven by the input shaft and in cludin g aflexible driver plate coaxial with the output shaft and mounting a camfollower yieldingly urged into engagement with the cam means and a pinextending into the aperture in the member, the cam follower and pinbeing angularly spaced substantially about the axis of rotation of theplate whereby rotation of the input shaft rotates the output shaft, andas the cam follower rides over the cam means, the pin is advanced orretarded relative to the input shaft and provides for relative movementbetween the input and output shafts in accordance with the contour ofthe cam means to effect desired lead or lag of the output shaft relativeto the input shaft.

11. Variable cam corrector mechanism for effecting a desired lead or lagof an output shaft with respect to an input shaft, comprising a memberfixed to the output shaft and having an aperture therein, adjustable cammeans, cam follower means driven by the input shaft and including aspring driver plate coaxial with the output shaft and mounting a camfollower yieldingly urged into engagement with the cam means and a pinextending into the aperture in the member, the cam follower and pinbeing angularly spaced substantially 90 about the axis of rotation ofthe plate whereby rotation of the input shaft rotates the output shaftand, as the cam follower rides over the cam means, the spring plateflexes and the pin is advanced or retarded relative to the input shaftand provides for relative movement between the input and out put shaftsin accordance with the contour of the cam means to effect desired leador lag of the output shaft relative to the input shaft.

12. Cam follower means for drivably connecting an input shaft and anoutput shaft and providing for relative movement between the input andoutput shafts in accordance with the contour of cam means to effectdesired lead or lag of the output shaft relative to the input shaft,comprising a flexible driver plate having a hub portion for mounting thedriver plate and a spring tab portion secured to the hub portion at oneend and separated therefrom by a slot extending around the hub portiontoward the one end of the driver plate to permit the spring tab portionto flex relative to the hub portion, and a cam follower and a drivingelement mounted on the spring tab portion.

13. The structure of claim 12 wherein the cam follower and drivingelement are spaced angularly substantially 90.

14. The structure of claim 12 wherein the slot is substantially U-shapedand the base of the U is concentric with the hub portion.

15. The structure of claim -12 wherein the cam follower and drivingelement are spaced angularly substantially 90 and the slot issubstantially U-shaped and the base of the U is concentric with the hubportion.

No references cited.

DAVID J. WILLIAMOWSKY, Primary Examiner.

L. H. GERIN, Assistant Examiner.

1. IN A MECHANISM OF A TYPE INCLUDING AN INPUT SHAFT, AN OUTPUT SHAFT, ADEVICE ROTATABLE BY SAID INPUT SHAFT FOR DRIVINGLY CONNECTING SIAD INPUTAND OUTPUT SHAFTS, CAM MEANS, CAM FOLLOWER MEANS COAXIAL WITH ANDENGAGING SAID CAM MEANS TO ADJUST SAID CONNECTING DEVICE SO AS TO MOVETHE OUTPUT SHAFT RELATIVE TO THE INPUT SHAFT, THE IMPROVEMENTCOMPRISING: SAID CONNECTING DEVICE INCLUDING A PIN CARRIED BY THE CAMFOLLOWER EXTENDING IN A PARALLEL AND AN OFFSET POSITION TO SAID CAMAXIS, A SLOTTED DISC CARRIED BY AND IN COAXIAL RELATION TO THE OUTPUTSHAFT AND WHEREIN THE PIN IS SLIDABLY MOUNTED IN DRIVING RELATION IN THESLOT OF THE DISC SO AS TO DRIVINGLY CONNECT SAID INPUT AND OUTPUT SHAFTSAND THE PIN BEING ANGULARLY ADJUSTABLY BY THE CAM FOLLOWER MEANS FORANGULARLY ACTUATING SAID DISC SO AS TO ADJUST THE OUTPUT SHAFT RELATIVETO SAID INPUT SHAFT IN ACCORDANCE WITH THE CONTOUR OF THE CAM MEANS TOEFFECT A DESIRED LEAD OR LAG OF THE INPUT SHAFT RELATIVE TO THE OUTPUTSHAFT.